Lab Report: Health, Science and Medicine

EMERGENCY MEDICINE

CPR Gets an Update

For 50 years, CPR has been performed the same way: quick breaths into the victim's mouth, followed by chest compressions in a repeated cycle to get the heart beating again. But in recent years, studies have shown that doing away with rescue breathing and using chest compressions alone may be just as effective, if not more so, in resuscitating victims of cardiac arrest. That's why the American Heart Association is updating its guidelines and urging both trained and untrained rescuers to start with the compressions and either eliminate or delay mouth-to-mouth breathing in cases when a victim's heart has stopped.

There are both social and medical reasons for the shift. About a third of people who collapse from cardiac arrest never receive CPR, largely because bystanders are unsure or squeamish about delivering it the right way. Streamlining the procedure to include only compressions--which should be firm enough to depress the chest by about 2 in. (5 cm)--could make it easier for more people to attempt resuscitation. Medically, say experts, the body has enough oxygen to function for a few minutes after the heart stops, so using compressions to restore its pumping action should be the priority.

HORMONE THERAPY

Clarifying the Hazards of HRT

It's been eight years since a landmark study revealed that hormone replacement therapy (HRT) after menopause increases women's risk of breast cancer. That trial was halted three years early, once the harms came to light. But doctors--and their patients--have been wondering ever since whether the types of breast cancers linked to HRT actually increase the risk of dying from the disease.

Now they have their answer and, unfortunately, it's yes. An 11-year follow-up to the trial in which researchers compared cancer rates among women who had been randomly assigned to take HRT--an estrogen-progestin combination that can treat the hot flashes and night sweats associated with menopause--or placebo found that the hormone users had a 25% greater chance of developing invasive breast cancer and a 96% greater likelihood of dying from the disease than the control group did. Previous studies suggested that the cancers attributed to HRT were generally detected earlier and less likely to be fatal, but the new data prove otherwise. The cancers in the hormone users were more likely to involve the lymph nodes and therefore potentially more prone to spread beyond the breast.

The good news, however, is that the results should mean a further drop in breast-cancer deaths in coming years, since fewer women have been using HRT since 2002.

FROM THE LABS

Anti-Alzheimer's Vitamin?

The key to reversing the mental decline caused by Alzheimer's disease won't be as easy as popping a vitamin, but new research with a group of nearly 300 elderly people suggests that B[subscript 12] may help lower homocysteine, a compound linked to memory loss and stroke, and reduce the risk of Alzheimer's as well.

Genetic Roots of Alcoholism